Tool for assembling and disassembling an electrical connector



June 20, 1967 BUGHT ET AL 3,325,884

TOOL FOR ASSEMBLING AND DISASSEMBLING AN ELECTRICAL CONNECTOR Filed May 5, 1965 2 Sheets-Sheet 1 l/l/VEA/TORJ' D. J. BLIGHT P.J. GIBBINS June 20, 1967 D. J. BLIGHT ET AL TOOL FOR ASSEMBLING AND DISASSEMBLING AN ELECTRIQAL CONNECTOR Filed May 5, 1965 2 Sheets-Sheet 2 DJ- BLIGHT RJ.GIBBINS United States Patent 3,325,884 TOOL FGR ASSEMBLING AND DISASSEMELING AN ELECTRICAL CQNNECTOR Dennis Jack Blight, Camberley, and Peter James Gihbins, London, England, assignors to International Standard Electric Corporation, New York, N.Y., a corporation of Delaware Filed May 5, 1965, Ser. No. 453,276 Claims priority, application Great Britain, May 6, 1964, 18,811/ 64 Claims. (Cl. 29-203) This invention relates to assembling and disassembling tools for use with multi-contact plug connector of the type in which the contacts are retained in position by means of spring-loaded clips. A connector using such a so-called rearclip contact retention system is covered by British application No. 46,025/61 (Ser. No. 976,723) in the name of Cannon Electric (U.S.A.) Limited.

Plug connectors of this type are used to terminals interconnecting cables or cable forms which may comprise a great number of separate insulated conductors, and, where space is at a premium, as, for example, in aircraft electrical and electronic equipment, dimensions are scaled down to the minimum consistent with safety. In such cases easy insertion and withdrawal of individual conductors with their plug-ended terminations from the rear of the connector body for servicing is also of great importance, and for this purpose insertion and extraction tools have been devised which slip on to individual conductors for operating the spring-loaded clips.

A complication has, however, arisen in the use of the standard tools owing to the unavoidable mixing of different standards in the construction of the connectors and the leads with which they are to be associated in a particular instance, a complication which is not readily resolved by a straight-forward adaptation of the tools or a conforming to compatible standards. Arrangements will therefore be described in what follows for meeting this contingency, and the accompanying drawings illustrate a standard connector and an embodiment of a modified combined insertion and extraction tool for use with oversize conductors associated with a standard connector body.

According to the present invention there is provided a tool for inserting plug-ended conductor into, or for extracting such conductors from a connector of the type which uses rear-clip retention as herein referred to, which includes a hollow tubular member whose inner diameter is such as to fit over the conductor to be dealt with, and which member is longitudinally split so that it can be fitted over a conductor to be dealt with, wherein said member includes a first thin-walled portion which in use fits against the rear face of the shoulder section of the plug end of the conductor being dealt with, an intermediate portion of greater thickness and outside diameter than said first portion, and an outside portion of greater thickness and outside diameter than said intermediate portion which outside portion serves as a handle for the tool when in use.

In the drawings,

FIG. 1 is a perspective view of part of the face of a standard connector body with one plug-terminated conductor in position;

FIG. 2 shows in elevation the plug-terminated conductor of FIG. 1 before insertion;

FIG. 3 is a part-section view of a plug in position in the cavity with the insertion tool according to this invention fully inserted;

FIG. 4 is a similar view of a plug in position in the cavity with the extraction tool fully inserted;

FIG. 5 shows the modified combined insertion/extrac- Patented June 20, 1967 tion tool in plan view with end elevation of the insertion tool, and a central section at ZZ; and

FIGS. 6 and 7 together show a central longitudinal section of the combined tool of FIG. 5, FIG. 6 being the insertion portion; and FIG. 7 the extraction portion.

FIGS. 1 and 2 together show the components of a National Aerospace Standards connector to specification NAS 1599 (a U.S.A. Standard specification) in which plug-terminated insulated conductors are inserted into cavities 9 in a body 25 consisting of a hard dielectric moulding and retained in position by moulded-in rearclips (not visible in FIG. 1) having springy tines which engage with the back-face of the shoulder of the plug.

Each plug is made of metal, e.g. brass, and has a shoulder section 1 the back-face 2 of which terminates in a tubular portion 3 shown crimped at 4- on to the bared end of an insulated multi-strand conductor 5. This is shown partly sectioned to reveal the strands at 6. The front face of the shoulder is surmounted by a short thick section 7 (FIG. 1) which in turn terminates in a thinner plug-section 8, rounded at its end (see FIG. 1).

A typical connector may accommodate 48 such plugs, and FIG. 1 shows the hard dielectric portion of such a connector. The rear of the connector has a soft rubber grommet portion welded to it through which each plug has to pass and which serves to give the assembly of terminated conductors positional stability. The grommet portion is not shown in FIG. 1.

FIG. 3 shows a single cavity in the connector body in section, with a plug-terminated conductor in position in the cavity and shown in elevation, with, again in section, the insertion tool around the conductor and the cableentry end 3 of the plug.

In this figure, 16 represents the hard dielectric moulding and 11 the soft grommet at the back these two having an interface 12. An annular shoulder 13 at the mouth of the cavity (not otherwise referenced) provides a stop for the shoulder 1 of the plug in its forward movement, but allows the portion 7 of the plug body to protrude. Within the cavity there is a moulded-in rear-clip 14 which consists of a spring-steel cylinder split along its length (in a manner not shown in the figure) and with a pair of tines 15 opened on opposite sides of the cylinder and biased inwards, as shown; the split lies between the two tines, on one side, and the narrow rim 16 above the tines abuts against the back of the shoulder 13. When, therefore, the plug is in position in its cavity after full insertion from the rear, the shoulder 1 is trapped between the shoulder 13 and the inwardly-biased tines 15, with a very small clearance all around, as indicated.

The figure also shows the modified insertion tool in position around the conductor and plug at the position of full insertion. The tool consists of the portions 17, 18, 19 and 20, each of which has its individual functions, to be hereinafter described, and the tool itself is illustrated independently in FIG. 5 and 6-, which shows a combined insertion/extraction tool.

In the application to British practice of the connector as illustrated in FIG. 1, which conforms to certain U.S.A. standards, it has been found necessary to use it with insulated conductors made to a British standard which are oversize as compared with their U.S.A. counterparts. Thus, although the plug-ended conductors thus produced will enter the connector body without difficulty, the use of the standard tools for insertion and extraction (tools, that is, made in conformity with the U.S.A. standards) becomes impossible owing to the lack of clearance between the insulation of the conductor, if taken right up to the conductor entry point of the plug, and the wall of the cavity.

The general form of the tool, it will be seen from the figures, is a tubular device which fits over the insulation of the conductor and the rear end of the plug, the object of the insertion tool being to exert pressure on the shoulder of the plug to drive it through the connector into position in its appropriate cavity, while the object of the extraction tool is to force open the tines holding the plug in position to enable the plug to be withdrawn. Simple thinning of the walls of the standard tool to conform to the reduced clearances available is not good enough, as this weakens the tool excessively; while the gaining of clearance by failing to take the conductor insulation right up to the entry point of the plug is an unacceptable solution. The modified tool to be described operates with thinned-down walls but is provided with strengthening safeguards, and enables assembly and disassembly of connectors to proceed normally, as for fully standard equipment.

FIG. 5 shows a combined insertion and extraction tool (left and right of the figure respectively) with an end elevation of the insertion tool and a central section on ZZ. The tools have been made from Delrin (registered trademark) acetyl resin which combines stiffness with resilience. As will be seen from FIG. 5, the tool is slit on one side throughout its length, the edges of the slit meeting in the narrow portions of the tool while opening up sufliciently at the centre (widest portion) to allow the conductor to be fed into the bore easily. This enables the tool to be slipped on or off a conductor the ends of which are not accessible.

Considering first the insertion tool, shown in FIGS. 5 and 6, and in use in FIG. 3, the nose portions 17 and 18 are made very thin, the portion 17 tapering to a close fit on the rear part 3 of the plug, while the straight portion 18 is of a diameter just to enter the standard size entry to the cavity at the interface 12 in FIG. 3. The size of the insulated conductor and the diameter of the cavity at this point determine the maximum wall thickness possible, which in a particular instance is 0.006 inch. Beyond this point, section 19, the tool is allowed greater wall thickness while still retaining the same bore diameter, since the soft rubber grommet has sufficient resilience to accommodate such increased overall diameter, and further back still, outside the grommet, section 20, the tool opens out to the centre, handle portion.

The extraction tool, shown in FIGS. 5 and 7, and in use in FIG. 4, gives the most difiicult conditions to meet, since the tines of the rear-clip have to be opened by the very thin flexible wall at the tip of the tool.

Referring first to FIG. 4, it can be seen generally how the tool operates to enable extraction to be effected. The tip 21 of the tool pushes the tines outwards to be in line with the cylindrical walls of the rear-clip, and then the tool with the plug-ended conductor within it may be withdrawn as a whole past the opened tines which collapse behind the shoulder 1 of the plug. However, the conditions to be met are quite severe.

First, the flexible wall has a thickness determined in the same way as before, and in the same typical case has a maximum thickness of 0.006 inch, and this has to provide adequate thickness to operate the tines. In order to make this operationally possible, the length of this section has been reduced to the minimum possible, which is the length necessary to penetrate the cavity in the hard insulator section of the connector. Thus, in the fully inserted position of the tool, the transition at point 22 between the thinnest part of the wall 21 and the section 23 of the tool having the greater wall thickness occurs immediately behind the interface 12 of the hard insulator and the soft rubber grommet. At the same time, the section 23 of increased wall thickness is limited in length to that of the grommet-see FIG. 4. (The same principle applies to the insertion to0lsee FIG. 3.) Both sections 21 and 23 are of parallel form, as shown, and the transition between the parallel section 23 and the external tapered section 24 approximates in position to the rear face of the grommet when the tool is fully inserted, as FIG. 4 shows. This applies also to the insertion toolsee FIG. 3. This arrangement avoids unnecessary stretching of the rubber grommet sideways on each insertion of the tool, and in addition, the end of the tapered handle section of the tool provides visual evidence of the depth of penetration of the tool, i.e. whether or not the tool has been fully inserted.

The purpose of the increased wall thickness, 19 and 23 respectively, in the section of the tool which in the fully inserted position is enclosed by the grommet material is to provide adequate support for the thin section of the tool which enters the hard dielectric and either drives the plug forward (insertion tool) or operates the tines (extraction tool).

It will be appreciated that the clearances shown in FIGS. 3 and 4 are exaggerated for the sake of clarity and are in practice very much smaller, being of the order of one-thousandth of an inch. Moreover, the material mentioned for the tool is not the only possible material, which, as stated, must combine both stiffness and resilience, and moulded acetal, or polyamide plastic or equivalent material may be used.

As a general statement relative to this art, the National Aerospace Standards Connector Specification NAS 1599, which defines the contact insertion and withdrawal tool for use with rearclip retained contacts specified by the specification, covers a range of contact sizes numbered respectively 12, 16 and 20, in descending order of size.

Size No. 20, which is the size most difficult to accommodate in any mixing of standards and which has given rise to the herein-described improvements, is adapted for use with insulated conductors having an outside diameter of about 0.08 inch, whereas it is now required to accommodate conductors having an outside diameter of 0.09 inch, and this constitutes an embarrassing increase in size. The arrangements described provide a tool well able to deal with such larger conductors.

It is to be understood that the foregoing description of specific examples of this invention is not to be con.- sidered as a limitation on its scope.

What is claimed is:

1. A tool for assembling and disassembling an electrical connector having an insulation body provided with a bore therethrough with a front end and a rear end, a

plug-ended conductor releaseably mounted in the bore, and having an enlarged shoulder, an insulated wire attached to the conductor and extending rearwardly from the insulated body, the insulated wire having a diameter larger than the conductor, the insulated body including a forward section of hard material and a rear grommet section made of soft resilient material, the joint between the wire and the conductor being located within the hard section of the insulated body, means in the bore cooperating with the shoulder to limit forward movement of the conductor in the bore, releasable locking means extending between the conductor and the Wall of the bore engaging the rear of the shoulder to selectively control rearward withdrawal of the conductor, a rearwardly opening clearance between the bore walls surrounding the conductor and the wire with the clearance being very slight in the area of the insulated Wire which is within the hard section of the insulator body, said tool comprising: a hollow tubular member having an inner diameter which fits over the conductor and the wire, said member being longitudinally split so that it can fit over the conductor and being made of material which is circumferentially flexible and axially rigid, said member having a thin-walled portion which in use is inserted within the clearance between the bore and the conductor and wire to engage the rear face of the conduct-or shoulder, said member having an intermediate portion of greater wall thickness and outside diameter than said thin-walled portion, and being connected to said thinwalled portion by a short frusto conical portion, the

length of said thin-Walled portion being no greater than the dimension between the rear face of the conductor shoulder and the rear face of the hard section of the insulator body, said intermediate portion having a parallel cross-section and having an axial length approximately equal to the axial length of said grommet, and said member having an outer portion of greater wall thickness and outside diameter than said intermediate portion, said outside portion serving as a handle for the tool in use.

2. The tool of claim 1 wherein said thin Walled portion has a parallel cross-section and an outer diameter such that the releasable locking means is released by said thin-walled portion in operation.

3. The tool of claim 1 wherein the forward end of said thin-walled section is tapered inwardly to engage the sides of the conductor while engaging the rear face of the conductor shoulder, and the outside diameter of the thin-Walled portion is positioned so that the releasable locking means is permitted to remain in looking position.

4. The tool of claim 2 wherein the opposite end of said member is formed with the identical structure recited except that the forward end of the thin-Walled portion on said opposite end is tapered inwardly to engage the side of the conductor While engaging the rear face of the conductor shoulder, and the outside diameter of the thin- Walled portion is of a size to permit the releasable locking means to remain in locking position, whereby one end of said member serves as a conductor release tool and said opposite end serves as a conductor insertion tool.

5. The tool of claim 1 wherein the wall thickness of said thin-walled section is not greater than .006 inch.

References Cited UNITED STATES PATENTS 2,638,025 5/1953 Nelson 29-270 3,110,093 11/1963 Johnson 29-203 3,170,230 2/ 1965 Gaizauskas 29203 3,197,849 8/1965 Johnson 29203 JOHN F. CAMPBELL, Primary Examiner. THOMAS H. EAGER, Examiner. 

1. A TOOL FOR ASSEMBLING AND DISASSEMBLING AN ELECTRICAL CONNECTOR HAVING AN INSULATION BODY PROVIDED WITH A BORE THERETHROUGH WITH A FRONT END AND A REAR END, A PLUNG-ENDED CONDUCTOR RELEASABLY MOUNTED IN THE BORE, AND HAVING AN ENLARGED SHOULDER, AN INSULATED WIRE ATTACHED TO THE CONDUCTOR AND EXTENDING REARWARDLY FROM THE INSULATED BODY, THE INSULATED WIRE HAVING A DIAMETER LARGER THAN THE CONDUCTOR, THE INSULATED BODY INCLUDING A FORWARD SECTION OF HARD MATERIAL AND A REAR GROMMET SECTION MADE OF SOFT RESILIENT MATERIAL, THE JOINT BETWEEN THE WIRE AND THE CONDUCTOR BEING LOCATED WITHIN THE HARD SECTION OF THE INSULATED BODY, MEANS IN THE BORE COOPERATING WITH THE SHOULDER TO LIMIT FORWARD MOVEMENT OF THE CONDUCTOR IN THE BORE, RELEASABLE LOCKING MEANS EXTENDING BETWEEN THE CONDUCTOR AND THE WALL OF THE BORE ENGAGING THE REAR OF THE SHOULDER TO SELECTIVELY CONTROL REARWARD WITHDRAWAL OF THE CONDUCTOR, A REARWARDLY OPENING CLEARANCE BETWEEN THE BORE WALLS SURROUNDING THE CONDUCTOR AND THE WIRE WITH THE CLEARANCE BEING VERY SLIGHT IN THE AREA OF THE INSULATED WIRE WHICH IS WITHIN THE HARD SECTION OF THE INSULATOR BODY, SAID TOOL COMPRISING: A HOLLOW TUBULAR MEMBER HAVING AN INNER DIAMETER WHICH FITS OVER THE CONDUCTOR AND THE WIRE, SAID MEMBER BEING LONGITUDINALLY SPLIT SO THAT IT CAN FIT OVER THE CONDUCTOR AND BEING MADE OF MATERIAL WHICH IS CIRCUMFERENTIALLY FLEXIBLE AND AXIALLY RIGID, SAID MEMBER HAVING A THIN-WALLED PORTION WHICH IN USE IS INSERTED WITHIN THE CLEARANCE BETWEEN THE BORE AND THE CONDUCTOR AND WIRE TO ENGAGE THE REAR FACE OF THE CONDUCTOR SHOULDER, SAID MEMBER HAVING AN INTERMEDIATE PORTION OF GREATER WALL THICKNESS AND OUTSIDE DIAMETER THAN SAID THIN-WALLED PORTION, AND BEING CONNECTED TO SAID THINWALLED PORTION BY A SHORT FRUSTO CONICAL PORTION, THE LENGTH OF SAID THIN-WALLED PORTION BEING NO GREATER THAN THE DIMENSION BETWEEN THE REAR FACE OF THE CONDUCTOR SHOULDER AND THE REAR FACE OF THE HARD SECTION OF THE INSULATOR BODY, SAID INTERMEDIATE PORTION HAVING A PARALLEL CROSS-SECTION AND HAVING AN AXIAL LENGTH APPROXIMATELY EQUAL TO THE AXIAL LENGTH OF SAID GROMMET, AND SAID MEMBER HAVING AN OUTER PORTION OF GREATER WALL THICKNESS AND OUTSIDE DIAMETER THAN SAID INTERMEDIATE PORTION, SAID OUTSIDE PORTION SERVING AS A HANDLE FOR THE TOOL IN USE. 